Modern semi-automatic firearms are often designed to be fed ammunition (e.g., rounds or cartridges) from a removable magazine. Typically, the magazine includes a tubular housing of generally rectangular cross-section capable of holding one or two columns of cartridges. A follower is mounted on a strong spring at the bottom of the housing to urge the cartridges upwardly toward the open end of the magazine so that a cartridge is always in position to be fed into the chamber after a round is discharged. A pair of lips or flanges at the open end of the magazine engage the cartridge casing to prevent the cartridges from moving vertically beyond the magazine, while allowing the uppermost cartridge to be fed laterally into the chamber of the firearm. Handgun or pistol magazines expose only a single round between both lips, the gap between which is too narrow to allow a cartridge to pass through, whereas magazines for rifles typically have lips that are spaced further apart to expose two rounds between the lips. The configuration of the lips at the open end of a pistol magazine, coupled with the strength of the spring, makes loading cartridges into a pistol magazine particularly difficult. The casing of each cartridge must be located forwardly of the lips and pressed downwardly against the uppermost cartridge in the magazine with great force, usually with one's fingers, until the casing clears the lips and can be slid laterally under the lips to properly seat the cartridge in the magazine. The process is repeated for each cartridge and can be painful and time consuming when loading large capacity magazines.